Color photographic silver halide negative working duplicating elements, especially films, have been known, especially for duplicating color motion picture films. A typical example of such a duplicating element is Eastman Color Intermediate Film manufactured and sold by Eastman Kodak Company, U.S.A. Such a duplicating element is useful in preparing duplicates of motion picture film. The usual construction of such element is to have three records, each record having one or more layers containing emulsions sensitive to different regions of the spectrum, namely the red, green and blue light sensitive layers. Those layers contain color forming compounds which produce cyan, magenta and yellow dyes, respectively, in accordance with the amount of light of red, green and blue colors to which the film is exposed. The records are arranged with the red record lowest (that is, furthest from the light source when the film is exposed in a normal manner), followed by the green record above the red record and the blue record above the green record.
Current practice for most color motion picture production involves the use of at least four photographic steps. The first step is the recording of the scene onto a camera negative photographic film. For applications using two steps this original negative is printed onto a negative working print film, producing a direct print. Most motion picture productions use an additional two steps. The original camera negative film is printed onto a negative working intermediate film, such as the described Eastman Color Intermediate Film, yielding a master positive. The master positive is subsequently printed again onto an intermediate film providing a duplicate negative. Finally, the duplicate negative is printed onto a print film forming the release print. In certain situations, usually involving special effects, the intermediate film may be used four times. In this case, the produced master positive is used to produce a first duplicate negative which is then used to produce a second master positive, which is in turn used to produce a second duplicate negative. The second duplicate negative is used for printing the release print.
Given the number of copies which are made sequentially from the intermediate film it is desirable that the intermediate film produce a negative that enables a print with a minimum degradation in tone scale, color, graininess, and sharpness when compared to the direct print. A known sharpness measurement is acutance. Any sharpness loss (that is, loss in acutance) in the intermediate film will be increased dramatically due to the sequential copying using the intermediate film, as described. Thus, an unacceptable lowering of acutance in the release print as compared to the direct print (which is the most appropriate comparison), may result. Ideally, the intermediate film would produce no degradation of sharpness. In practice, there has always been some sharpness degradation which results in considerable sharpness loss in the sequential copying process described above to produce the release print.